GB2038985A - Method of preventing "pumping-up" of a hydraulic valve-clearance adjusting element in the valve drive train of an internal combustion engine - Google Patents
Method of preventing "pumping-up" of a hydraulic valve-clearance adjusting element in the valve drive train of an internal combustion engine Download PDFInfo
- Publication number
- GB2038985A GB2038985A GB7941487A GB7941487A GB2038985A GB 2038985 A GB2038985 A GB 2038985A GB 7941487 A GB7941487 A GB 7941487A GB 7941487 A GB7941487 A GB 7941487A GB 2038985 A GB2038985 A GB 2038985A
- Authority
- GB
- United Kingdom
- Prior art keywords
- valve
- drive train
- rod
- force
- cam
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/20—Adjusting or compensating clearance
- F01L1/22—Adjusting or compensating clearance automatically, e.g. mechanically
- F01L1/24—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically
- F01L1/2405—Adjusting or compensating clearance automatically, e.g. mechanically by fluid means, e.g. hydraulically by means of a hydraulic adjusting device located between the cylinder head and rocker arm
Description
1
GB 2 038 985 A 1
SPECIFICATION
Method of preventing the inflation or "pumping-up" of a hydraulic valve-clearance adjusting element in the valve drive train of an 5 internal combustion engine, and valve drive train for performing this method.
This invention relates to a method of preventing the inflation or "pumping-up" of a hydraulic valve-clearance adjusting element in the valve drive train 10 of an internal combustion engine, the valve drive train including a cam-driven valve-actuating lever mounted by means of the valve-clearance adjusting element.
Particularly when an internal combustion 15 engine operates at high speeds, physical contact is sometime lost between the valve-actuating lever and the cam of the camshaft. This produces what is called "valve flight". When hydraulic valve-clearance adjusting elements are used, this 20 phenomenon leads to what is called "inflation" or "pumping-up" of these elements as they automatically adjust, so that the valves are then unable to close.
An aim of the invention is to provide a method 25 of preventing inflation of the hydraulic valve-clearance adjusting elements in internal combustion engines having a valve drive of the construction set forth in the opening paragraph of this Specification. Another aim is to provide a 30 valve drive train for performing this method. With a view to meeting the first mentioned aim, the invention is directed to a method comprising the step of applying to the valve-clearance adjusting element during the period that the valve is opened 35 by the cam an additional force, i.e. a force in addition to any force generated in the valve train as'a direct result of opening or closing of the valve which is spring biased towards a closed position, such additional force acting against the adjusting 40 force of the valve-clearance adjusting element being preferably greater than the balancing force, and being independent of the drive train force which the valve-actuating lever applies to the valve-clearance adjusting element.
45 With a view to achieving the second mentioned aim, the invention is directed to a valve drive train comprising a cam driven valve actuating lever mounted by means of a hydraulic valve-clearance adjusting element, and means to apply to said ■ 50 element during the period that the valve is opened . by the cam a force in addition to any force generated in the valve train as a direct result of opening or closing a valve spring biased towards a closed position, said means comprising a rod 55 which bears resiliency on the valve actuating lever with a force which varies cyclicly and is higher when the cam is in a valve-opening position than it is when the cam is not in a valve-opening position, said cyclic force acting against the 60 adjusting force of the valve clearance adjusting element.
By means of the method of the invention in conjunction with a valve drive train according to the invention, it becomes possible to prevent
65 inflation of the valve-clearance adjusting element in an effective manner when the valve is open, whilst the valve clearance adjustment is not affected whilst the valve is closed.
A preferred embodiment of a valve drive train 70 according to the invention will now be described by way of example and with reference to the accompanying drawings, in which:
Figure 1 is a section through a cylinder head of an internal combustion engine, only essential 75 details of which are shown, a valve drive train being arranged therein in what is called a valve chamber; and
Figure 2 is a sectional plan view of the cylinder head of Figure 1 drawn along line II—II of that 80 Figure.
A valve drive train is arranged in the valve chamber 1 of a cylinder head 2 of an internal combustion engine, only essential details of which are illustrated. The valve drive train consists 85 essentially of a camshaft 3, a valve actuating lever
4 and a valve-clearance adjusting element 5. No details of the element 5 are shown since these are of well known conventional design. It will be understood however that the height of the
90 element 5 is automatically adjusted to achieve correct valve clearance during engine operation and when the engine valve is closed. The element
5 extends under a combined spring and hydraulic force to take up excessive play. The lever 4 is
95 mounted on the valve-clearance adjusting element 5 by means of a ball joint. A bifurcated resilient rod 6 in the form of a leaf spring is rigidly clamped in a wall 9 of the valve chamber 1 by means of the open end 7 of its bifurcated portion 8, and its free 100 end 10 terminates above the lever 4 in the zone of the bearing point 11 of the lever 4. At the side opposite the valve-clearance adjusting element 5, the rod 6 bears against the lever 4 by way of a compression spring 12. Furthermore, the resilient 105 rod 6, by way of the arms 13 of its bifurcated portion 8, bears at both sides against bearing faces 14 of the lever 4, which bearing faces are provided adjacent its slide face 15 which the cam engages and are disposed opposite thereto on the 110 lever 4.
The spring forces of the substantially straight clamped bar 6 and the compression spring 12 are so selected that, when the valve is closed, they are lower than the balancing force, consisting of the 115 oil pressure and spring force, in the valve-
clearance balancing element 5. When the cam lobe presses on to the slide face 15 of the lever 4, the rod 6 together with the lever 4 is depressed, and the force occurring at the free end 10 of the 120 rod 6 is increased and exceeds the balancing force. This prevents inflation of the element 5 (by preventing valve flight) whilst the valve is open, but it does not affect the valve clearance adjusting function of the element 5 when the valve is 125 closed.
Advantageously, the distance between the arms 13 of the bifurcated portion 8 is so related to the width of the lever 4 that lateral guiding of the lever is achieved. Machining of the end of the
2
GB 2 038 985 A 2
pulling lever 4 that bears against the valve spindle can thus be rendered easier, since no lateral guide feces require to be machined.
Suitably amended, this principle can also be 5 applied in the case of rocker arms.
Claims (1)
1. A method of preventing the inflation or "pumping up" of a hydraulic valve-clearance adjusting element in the valve drive train of an
10 internal combustion engine, the valve drive train including a cam-driven valve-actuating lever mounted by means of the valve-clearance adjusting element, the method comprising the step of applying to the valve-clearance adjusting 15 element during the period that the valve is opened by the cam, an additional force, i.e. a force in addition to any force generated in the valve train as a direct result of opening or closing of the valve which is spring biased towards a 20 closed position, such additional force acting against the adjusting force of the valve-clearance adjusting element, being preferably greater than the balancing force, and being independent of the drive train force which the valve-actuating lever 25 applies to the valve-clearance adjusting element.
2. A valve drive train comprising a cam driven valve actuating lever mounted by means of a hydraulic valve clearance adjusting element, and means to apply to said element during the period
30 that the valve is opened by the cam a force in addition to any force generated in the valve train as a direct result of opening or closing a valve spring biased towards a closed position, said means comprising a rod which bears resiliency on 35 the valve actuating lever with a force which varies cyclicly and is higher when the cam is in a valve-opening position that it is when the cam is not in a valve-opening position, said cyclic force acting against the adjusting force of the valve clearance
40 adjusting element.
3. A valve drive train according to claim 2, in which the rod is arranged substantially parallel to the valve-actuating lever, the rod bearing resiliently on the lever in the region where the
45 lever bears on the valve clearance adjusting element, a portion of the rod being subject to cam forces.
4. A valve drive train according to claim 3," in which the cam forces are transmitted to the rod by
50 the valve actuating lever which engages the rod.
5. A valve drive train according to claim 4, in which a bearing face formed on the valve-actuating lever and engaging the rod is disposed adjacent and opposite a slide face of the lever
55 against which the cam bears.
6. A valve drive train according to any of claims 2 to 5, in which the rod comprises a spring leaf rigidly mounted at one end.
7. A valve drive train according to claim 5, or
60 claims 5 and 6, in which the rod has a bifurcated portion and bears by way of arms of the bifurcated portion against the bearing face disposed on both sides of the valve-actuating lever.
8. A valve drive train according to claims 6 and
65 7, in which the rod is rigidly mounted at the end of its bifurcated portion, and its other end bears resiliently on the actuating lever.
9. A valve drive train according to any one of claims 2 to 8, in which a compression spring is
70 arranged between the valve-actuating lever and the rod.
10. A valve drive train substantially as described herein with reference to the accompanying drawing.
Printtd for Her Majesty's Stationery Office by the Courier Press, Leamington Spa, 1980. Published by the Patent Office, 25 Southampton Buildings, London, WC2A1 AY, from which copies may be obtained.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2852293A DE2852293C2 (en) | 1978-12-02 | 1978-12-02 | Method and device for preventing the inflation of a hydraulic valve lash adjuster |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2038985A true GB2038985A (en) | 1980-07-30 |
| GB2038985B GB2038985B (en) | 1982-09-29 |
Family
ID=6056215
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7941487A Expired GB2038985B (en) | 1978-12-02 | 1979-11-30 | Method of preventing "pumping-up" of a hydraulic valve-clearance adjusting element in the valve drive train of an internal combustion engine |
Country Status (6)
| Country | Link |
|---|---|
| US (2) | US4359019A (en) |
| JP (1) | JPS5936086B2 (en) |
| DE (1) | DE2852293C2 (en) |
| FR (1) | FR2442962A1 (en) |
| GB (1) | GB2038985B (en) |
| IT (1) | IT1127666B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4869215A (en) * | 1987-05-21 | 1989-09-26 | Jaguar Cars Limited | Cam mechanisms |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2852293C2 (en) * | 1978-12-02 | 1980-12-11 | Bayerische Motoren Werke Ag, 8000 Muenchen | Method and device for preventing the inflation of a hydraulic valve lash adjuster |
| US4738231A (en) * | 1980-03-27 | 1988-04-19 | Toledo Stamping & Manufacturing Company | One-piece rocker arm with insert |
| JPS60190904U (en) * | 1984-05-29 | 1985-12-18 | スズキ株式会社 | Rocker arm control device for hydraulic tappet device |
| JPS6114407A (en) * | 1984-06-29 | 1986-01-22 | Honda Motor Co Ltd | Valve gear for internal-combustion engine |
| JPS6181503A (en) * | 1984-09-28 | 1986-04-25 | Honda Motor Co Ltd | Valve gear for internal-combustion engine |
| JPS634307U (en) * | 1986-06-25 | 1988-01-12 | ||
| DE3712020A1 (en) * | 1987-04-09 | 1988-10-27 | Schaeffler Waelzlager Kg | VALVE CONTROL DEVICE |
| DE10043592A1 (en) * | 2000-09-01 | 2002-03-14 | Stihl Maschf Andreas | Lubrication for a cam drive |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3124115A (en) * | 1964-03-10 | Voorhies | ||
| US1792795A (en) * | 1927-12-24 | 1931-02-17 | Gen Motors Res Corp | Hydraulic valve gear |
| US1931476A (en) * | 1929-12-19 | 1933-10-17 | George E A Hallett | Hydraulic valve lash adjusting mechanism |
| FR827696A (en) * | 1936-10-10 | 1938-05-02 | Improvements to push-button mechanisms | |
| US2615438A (en) * | 1948-08-04 | 1952-10-28 | Preston T Tucker | Hydraulic mechanism for actuating valves |
| DE939057C (en) * | 1952-11-04 | 1956-02-16 | Porsche Kg | Adjustment device for valve controls of internal combustion engines |
| US3045657A (en) * | 1959-07-22 | 1962-07-24 | Thompson Ramo Wooldridge Inc | Valve operating means |
| US3463131A (en) * | 1968-03-12 | 1969-08-26 | John W Dolby | Valve operating mechanism |
| DE2416910B2 (en) * | 1974-04-06 | 1977-08-04 | Daimler Benz Ag, 7000 Stuttgart | ACTUATING DEVICE FOR THE WORK MEDIA VALVES ON A PISTON MACHINE WITH HYDRAULIC VALVE CLEARANCE COMPENSATING ELEMENTS |
| US4098240A (en) * | 1975-02-18 | 1978-07-04 | Eaton Corporation | Valve gear and lash adjustment means for same |
| JPS53123310U (en) * | 1977-03-09 | 1978-09-30 | ||
| DE2852293C2 (en) * | 1978-12-02 | 1980-12-11 | Bayerische Motoren Werke Ag, 8000 Muenchen | Method and device for preventing the inflation of a hydraulic valve lash adjuster |
-
1978
- 1978-12-02 DE DE2852293A patent/DE2852293C2/en not_active Expired
-
1979
- 1979-11-27 JP JP54152528A patent/JPS5936086B2/en not_active Expired
- 1979-11-29 IT IT27684/79A patent/IT1127666B/en active
- 1979-11-30 GB GB7941487A patent/GB2038985B/en not_active Expired
- 1979-12-03 FR FR7929697A patent/FR2442962A1/en active Granted
- 1979-12-03 US US06/100,026 patent/US4359019A/en not_active Expired - Lifetime
-
1982
- 1982-04-16 US US06/369,029 patent/US4418659A/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4869215A (en) * | 1987-05-21 | 1989-09-26 | Jaguar Cars Limited | Cam mechanisms |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5936086B2 (en) | 1984-09-01 |
| IT7927684A0 (en) | 1979-11-29 |
| US4359019A (en) | 1982-11-16 |
| JPS5575518A (en) | 1980-06-06 |
| DE2852293C2 (en) | 1980-12-11 |
| US4418659A (en) | 1983-12-06 |
| DE2852293B1 (en) | 1980-04-17 |
| GB2038985B (en) | 1982-09-29 |
| FR2442962B1 (en) | 1983-03-18 |
| IT1127666B (en) | 1986-05-21 |
| FR2442962A1 (en) | 1980-06-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |